Tunable Emission Enhancement in Surface Plasmon‐Enhanced GaN Light‐Emitting Diode Based on the Ag–SiO2 (Ag‐Rich) Cermet Material

Abstract

The metal–dielectric cermet (metal‐rich) material is utilized for turning the dispersion properties of surface plasmon in GaN‐light‐emitting diode. The designed structure contains a cermet layer coated on p‐GaN layer. The optimized ingredients in the cermet material and thickness of the cermet layer are obtained by the simulations. For enhancing the extraction of surface plasmon, the designed structure is further optimized by inserting a layer of low refractive index. The calculated results indicate that the Purcell factor in optimized structure is greater than 100 over the emission spectrum and the extraction efficiency of surface plasmon is effectively improved. The photoluminescence (PL) experiment by bottom excitation demonstrates that peaks of PL spectra of the designed and optimized samples are enhanced by 1.6 and 3.4 times, respectively, compared with the sample covered by Ag film. Compared with the naked sample, peaks of PL spectra of bottom pumping of optimized and designed samples are enhanced by 36.3 and 17.2 times, respectively. Peaks of normalized PL spectra by top excitation of optimized and designed samples are enhanced by 29.0 and 9.1 times, respectively. The results of numerical calculations are substantially consistent with the results of PL tests.